Recently, as the CPU driving frequency has been becoming higher (e.g., 10 GHz or higher), attention has been directed toward optical interconnection techniques in which signals within and between system apparatus are transmitted by light. Semiconductor devices such as semiconductor photodetector devices and semiconductor light-emitting devices are used in the optical interconnection techniques.
Japanese Patent Application Laid-Open Nos. HEI 2-128481, 10-200200, and 11-46038 disclose so-called back-emitting semiconductor light-emitting devices each comprising a substrate and a plurality of compound semiconductor layers laminated on one of main faces of the substrate and emitting light from the other main face of the substrate. For the following purposes, the portion of substrate positioned under the light-emitting region is partially thinned in these semiconductor light-emitting devices, while a part maintaining the substrate thickness is formed so as to surround the above-mentioned part. The first purpose is to prevent optical signals from deteriorating or disappearing because of optical absorption of the substrate. The second purpose is to prevent the semiconductor devices from being damaged or broken when mounted onto an external substrate by wire-bonding or bump-bonding.